It's true, I gave up with my (admitedly cheap) tv sender as neither it or the wireless could cope with each others interference, even after trying different combinations of channels.

As for microwaves while in theory they do interfere in practice they are generally reasonably sheilded and more to the point not used for more than a few minutes a day - in fact if these surveys were done during the daytime then there is probably a very good chance that none were used within the range of the detectors.